Discharge Characteristics Of Unbalanced Magnetron Sputtering Technique And MF Magnetron Sputtering Technique And Preparationof Cr-DLC Films

Metal containing diamond-like carbon coatings are widely used in anti-friction areas because of high hardness, resistance to friction and low wear rate. For conventional magnetron sputtering technology, the process is hampered by low deposition rates and the occurrence of arc events at the target, which are detrimental to the structure, properties and composition of the coating. Unbalanced magnetron sputtering technique and MF magnetron sputtering technique are excellent methods for preparation of Cr-DLC films featured by preventing arc events and stabilizing the reactive sputtering process.Unbalanced magnetron sputtering technique and MF magnetron sputtering technique were used to investigate discharge characteristics of Cr target and the discharge characteristics of two techniques were compared. Cr-DLC films prepared under the same conditions target current use two techniques separately. The effect of distance of target to substrate on the morphology, phase structures, micro-hardness, wear resistance adhesion strength and electrochemical corrosion of deposited films were researched.MF pulse magnetron sputtering discharge characteristics results show that the target voltage and the substrate current increase as the pressure decrease. With the increases of N2 rate, the target voltage increases and then decreases, the base current value has been reduced. With the increases of C2H2 ratio, the target voltage decreases and then increases, the bias current is essentially unchanged.Unbalanced DC magnetron sputtering discharge characteristics results show that the CFUBM field-type is easier to obtain a higher bias current than MF field-type and UBM field-type. In the CFUBM field-type condition, with the increases of N2 rate, the bias current increases and then decreases, the target voltage decreases and then increases. With increases of C2H2 ratio, the target voltage increases, the base current decreases.The comparison of two magnetron sputtering discharge characteristics shows that, at the same condition of target current, the MF pulse magnetron sputtering has higher target voltage and higher target power than unbalanced DC magnetron sputtering. At the same condition of Ar: C2H2 ratio, the MF pulse magnetron sputtering can get a higher bias current.Cr-DLC film structure showed that, at the condition of unbalanced DC magnetron sputtering, Cr-DLC film is a columnar grain structure. With increasing the distance of target to substrate, the film thickness remains unchanged. The film mainly consists of the amorphous diffuse scattering peak and Cr2 C diffraction peak position, the Cr(110) peak is also found. At the condition of MF pulse magnetron sputtering, Cr-DLC film is dense columnar grain structure. With increasing distance of the target to substrate, the film thickness decreases. The film mainly consists of structure of nanocrystalline carbide confirmed by the amorphous diffuse scattering peak. Raman spectra shows two films prepared by magnetron sputtering are DLC films.Cr-DLC film performance tests show that, at the condition of unbalanced DC magnetron sputtering, Cr-DLC film has good adhesion, when the distance of target to substrate is 80 mm, the bonding class is HF1. The friction coefficient of the film increases with the distance of target to substrate increasing, electrochemical corrosion resistance decreases with the distance of target t o substrate increasing. At the condition of MF pulse magnetron sputtering, the bonding class is HF4. But the friction coefficient and anti-electrochemical corrosion ability are better than Cr-DLC films prepared by unbalanced DC magnetron sputtering.